Trap passivation and efficiency improvement of perovskite solar cells by a guanidinium additive

Incorporation of an effective additive 1,3-diaminoguanidine monohydrochloride in MAPbI₃ film can increase the grain size and reduce trap density, consequently increasing the carrier lifetime and reducing charge recombination, leading to an improved efficiency from 19.1% to 20.3% in a p–i–n structured solar cell.